Dipeptidyl peptidase-3 is associated with severity of liver disease and circulatory complications in patients with cirrhosis

Peptidylglycine α-amidating monooxygenase and adrenomedullin measurement in patients with hepatic cirrhosis

Background: Peptidylglycine α-amidating monooxygenase (PAM) is an enzyme involved in the maturation of regulatory peptides. Here we examined PAM activity and adrenomedullin (bio-ADM) concentrations in patients with hepatic cirrhosis and determined net changes across the liver, kidneys and leg. Materials & methods: A total of 48 patients with hepatic cirrhosis and 16 control subjects were included. All patients and controls underwent an invasive procedure with blood collected across organs. Results: PAM activity was increased in cirrhotic patients but without a net change across the liver, leg or kidney. In contrast, bio-ADM concentrations were associated with severity of disease and found to be higher in venous blood from the liver. Conclusion: Increased PAM activity in patients with hepatic cirrhosis may reflect other organs involved in cirrhotic disease.

Circulating dipeptidyl peptidase 3 and bio-adrenomedullin levels are associated with impaired outcomes in critically ill COVID-19 patients: a prospective international multicentre study

Introduction

Dipeptidyl peptidase-3 (DPP3) is a protease involved in the degradation of several cardiovascular mediators. Adrenomedullin (bio-ADM) is a peptide essential for regulation of endothelial barrier function. In different shock-pathologies, both biomarkers are associated with disease severity, organ dysfunction and mortality. Associations with outcome in critically ill COVID-19 patients are unknown. The objectives of the present study were to investigate associations of bio-ADM and "circulating DPP3" (cDPP3) with short-term outcome in critically ill COVID-19 patients (n=80).

Methods

A multicentre prospective cohort study was performed. The primary end-point was 28-day mortality. Secondary end-points included different severities of acute kidney injury (AKI).

Results

cDPP3 levels were mainly associated with 28-day mortality; Area under the receiver operating characteristics (AUROCs) of 0.69 (0.56-0.82, p=0.023), 0.77 (0.64-0.90, p<0.001) and 0.81 (0.65-0.96, p<0.001) at admission, day 3 and day 7, respectively. In contrast, bio-ADM levels were mainly associated with AKI, with AUROCs of 0.64 (0.51-0.77, p=0.048), 0.75 (0.64-0.86, p<0.001) and 0.83 (0.74-0.93, p<0.001) for day 1, 3 and 7, respectively. Interestingly, patients with high levels of both cDPP3 and bio-ADM at day 7 had an additionally increased risk of 28-day mortality (hazard ratio 11.8; 95% CI 2.5-55.3, p<0.001).

Conclusions

cDPP3 and bio-ADM responses were associated with short-term mortality and AKI in critically ill COVID-19 patients, respectively. These findings suggest that treatment with specific antibodies modulating cDPP3 or bio-ADM-related pathways may improve outcome of COVID-19.

Dipeptidyl Peptidase 3 Activity as a Promising Biomarker of Bone Fragility in Postmenopausal Women

The dipeptidyl peptidase 3 (Dpp3) is a ubiquitous zinc-dependent aminopeptidase, participating in the activation or degradation of signaling peptides and in the Keap1−Nrf2 antioxidant pathway. The absence of Dpp3 in the Dpp3 knockout mouse model causes increased osteoclast activity, altered osteogenic function, sustained oxidative stress in the bone tissue, and bone loss. We aimed to assess the association of Dpp3 activity with bone fragility in postmenopausal osteoporosis and the impact of denosumab on enzymatic activity. We conducted a two-phase study including 69 postmenopausal women with severe osteoporosis and 36 postmenopausal women without osteometabolic conditions, as controls (cross-sectional phase). Subjects with severe osteoporosis were assessed at baseline and 14 days after the first denosumab administration (prospective phase). The results showed significant reduction in serum Dpp3 activity (expressed as nmoles of formed product/mg proteins/min) in patients vs. controls (0.791 ± 0.232 vs. 1.195 ± 0.338; p < 0.001), and significant association with bone mass at the femoral neck (r = 0.28, p = 0.02) in patients prior to treatment. We found a negative correlation between C-terminal telopeptide (CTX) or N-terminal pro-peptide of type 1 procollagen (P1NP) levels and Dpp3 activity (respectively, r = −0.29, p = 0.012; and r = −0.2572, p = 0.033). Dpp3 activity did not change after denosumab injection. Our findings support a critical role played by Dpp3 in bone homeostasis as a potential bone protective factor. Additional clinical studies in larger cohorts might explore the implementation of Dpp3 assessment as a biomarker of bone health status.